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Biblioteca(s): |
Embrapa Caprinos e Ovinos. |
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Data corrente: |
06/10/2008 |
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Data da última atualização: |
15/01/2025 |
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Autoria: |
VAN SOEST, P. J. |
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Título: |
Impact of feeding behaviour and divestive capacity on nutritional response. |
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Ano de publicação: |
1980 |
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Fonte/Imprenta: |
In: FAO. Animal genetic resources conservation and management: proceedings of the FAO/UNEP technical consultation. Rome, 1981. Cap. 11. p. 140-161. |
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Idioma: |
Inglês |
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Conteúdo: |
The digestive efficiency of herbivores, ruminants and non-ruminants is determined by the relative capacity of the digestive tract and the respective animal requirements. The volumetric capacity of the digestive tract is related at a higher power to body weight (.9 - 1.1) than are requirements (.75) leading to the problem that smaller animals have smaller digestive tract size relative to their requirements. The consequence of a larger intake relative to gastrointestinal size is a faster rate of passage and lower degree of digestive extraction. The adaptive feeding responses of ruminants are divided into two main strategies: extraction of maximum available energy at the cost of feed intake, and selective feeding for dietary quality at the cost of eating time. These strategies correspond to the categories of grazer and browser respectively. Large differences occur in these abilities among extant species. Differences that may exist within species are insufficiently studied. The genetic adaptations to dietary strategy are dependent on various factors -body size and gastrointestinal capacity set limits for grazers, while mouth parts, learning ability, agility and/or gastrointestinal adaptation are determinants for browsers. The evolutionary selection for grazing strategy has very likely depended upon dry, cool temperate environments that favour nutrively undiffertiated forages of low lignification, while browsing strategy is favoured by highly differentiated and lignified plants that are characteristic of temperate forests and more generally tropical environments. Grazing behaviour presumes digestible cellulose and the feasability of the expense of rumination to be able to extract this energy resource. Browsing presumes that fibre is not worth the digestive effort and the less fibrous parts of plants are, therefore, sought after. The environmental relations of genetic adaptation of herbivores lead to the expectation that apparent digestive efficiencies of different animals are optimal under conditions where their adaptive ability can be expressed. Most of the controlled feeding studies have tended to eliminate this expression leading to artificial minimization of animal differences. MenosThe digestive efficiency of herbivores, ruminants and non-ruminants is determined by the relative capacity of the digestive tract and the respective animal requirements. The volumetric capacity of the digestive tract is related at a higher power to body weight (.9 - 1.1) than are requirements (.75) leading to the problem that smaller animals have smaller digestive tract size relative to their requirements. The consequence of a larger intake relative to gastrointestinal size is a faster rate of passage and lower degree of digestive extraction. The adaptive feeding responses of ruminants are divided into two main strategies: extraction of maximum available energy at the cost of feed intake, and selective feeding for dietary quality at the cost of eating time. These strategies correspond to the categories of grazer and browser respectively. Large differences occur in these abilities among extant species. Differences that may exist within species are insufficiently studied. The genetic adaptations to dietary strategy are dependent on various factors -body size and gastrointestinal capacity set limits for grazers, while mouth parts, learning ability, agility and/or gastrointestinal adaptation are determinants for browsers. The evolutionary selection for grazing strategy has very likely depended upon dry, cool temperate environments that favour nutrively undiffertiated forages of low lignification, while browsing strategy is favoured by highly differentiated and lignified plants... Mostrar Tudo |
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Palavras-Chave: |
Comportamento alimentar. |
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Thesagro: |
Digestibilidade; Nutrição Animal; Ruminante. |
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Thesaurus Nal: |
Digestibility; Feeding behavior; Ruminant nutrition. |
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Categoria do assunto: |
L Ciência Animal e Produtos de Origem Animal |
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Marc: |
LEADER 02906nam a2200193 a 4500
001 1533541
005 2025-01-15
008 1980 bl uuuu u00u1 u #d
100 1 $aVAN SOEST, P. J.
245 $aImpact of feeding behaviour and divestive capacity on nutritional response.$h[electronic resource]
260 $aIn: FAO. Animal genetic resources conservation and management: proceedings of the FAO/UNEP technical consultation. Rome, 1981. Cap. 11. p. 140-161.$c1980
520 $aThe digestive efficiency of herbivores, ruminants and non-ruminants is determined by the relative capacity of the digestive tract and the respective animal requirements. The volumetric capacity of the digestive tract is related at a higher power to body weight (.9 - 1.1) than are requirements (.75) leading to the problem that smaller animals have smaller digestive tract size relative to their requirements. The consequence of a larger intake relative to gastrointestinal size is a faster rate of passage and lower degree of digestive extraction. The adaptive feeding responses of ruminants are divided into two main strategies: extraction of maximum available energy at the cost of feed intake, and selective feeding for dietary quality at the cost of eating time. These strategies correspond to the categories of grazer and browser respectively. Large differences occur in these abilities among extant species. Differences that may exist within species are insufficiently studied. The genetic adaptations to dietary strategy are dependent on various factors -body size and gastrointestinal capacity set limits for grazers, while mouth parts, learning ability, agility and/or gastrointestinal adaptation are determinants for browsers. The evolutionary selection for grazing strategy has very likely depended upon dry, cool temperate environments that favour nutrively undiffertiated forages of low lignification, while browsing strategy is favoured by highly differentiated and lignified plants that are characteristic of temperate forests and more generally tropical environments. Grazing behaviour presumes digestible cellulose and the feasability of the expense of rumination to be able to extract this energy resource. Browsing presumes that fibre is not worth the digestive effort and the less fibrous parts of plants are, therefore, sought after. The environmental relations of genetic adaptation of herbivores lead to the expectation that apparent digestive efficiencies of different animals are optimal under conditions where their adaptive ability can be expressed. Most of the controlled feeding studies have tended to eliminate this expression leading to artificial minimization of animal differences.
650 $aDigestibility
650 $aFeeding behavior
650 $aRuminant nutrition
650 $aDigestibilidade
650 $aNutrição Animal
650 $aRuminante
653 $aComportamento alimentar
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